(1) Field of the Invention
The present invention, among other uses and applications, primarily relates to an improved method and system for precisely connecting components of curtain walls. Curtain walls are typically constructed by the assembly of support members comprising a complete frame for the support of a plurality of panels which, in turn, serve as a substantial part of the exterior of a building. The panels themselves may be of glass, granite, slate, concrete, or other materials.
The curtain walls will normally include a horizontal sill member, a horizontal head member, and numerous vertical mullions running between the sill and head members. Panel members are supported by grooved or u-shaped channels within the sill members and the head members. In some manufacturing processes screw splines or other integral mechanisms are fabricated within the interior of the mullion or usually, some portion of a shear block, to facilitate the attachment of horizontal members to the mullion or the attachment of the mullion to a concrete floor slab in a building under construction.
A common construction method involves the attachment of components such as shear blocks or clips to appropriate locations on the exterior or interior of vertical mullions. The horizontally-oriented head and sill members are thereafter affixed to the shear blocks, forming joints and support for the panel members. The present invention may be quickly and efficiently used to more precisely locate the drilling points for attachment holes on a vertical mullion or other workpiece. The inventive concept herein is also designed to simultaneously pinpoint the location of the necessary holes and apply the required fasteners through the shear block directly into the mullion.
(2) Description of the Related Art
Many different techniques and systems have been developed over the past fifty years for the purpose of constructing, assembling, and attaching vertical mullions, sills, head members, and the enclosed panel members to the structure of buildings. U.S. Pat. No. 3,147,518 (Horgan, 1964) was one of the earliest exhibiting the construction of curtain walls utilizing mullions comprised of extruded aluminum. The method disclosed drilling holes into the mullion and afterwards, the insertion of self-tapping screws to unite the mullion with horizontal members. Another consideration involved the factor of insulation and waterproofing, thus caulking was used extensively during construction.
As the various designs and means of connecting and securing frame members to each other and to the building structure evolved, the majority of methods were very similar. U.S. Pat. No. 3,961,452 (Hubbard et al, 1976) speaks of a screw spline system. The vertical mullions are drilled with holes in the appropriate places to receive shear pins. The horizontal members were attached by the insertion of the shear pins into screw splines formed in the horizontal member. The heads of the shear pins are then tapped downward until the shear pins bottom in the holes previously drilled in the mullions.
A stopless butt-joint multiple curtain wall system was disclosed in U.S. Pat. No. 5,355,645 (Farag, 1994) wherein a grid system is constructed from within a building under construction. One of the claims featured split mullion interlocking halves, each half secured to the other by interconnection of male to female connectors. Clips and retainers were also utilized for panels and receiving mullion, thus for the most part eliminating the need to drill holes.
In U.S. Pat. No. 6,158,182 (Biebuyck, 2000), disclosed is a method of assembling a curtain wall in a controlled environment within a factory, thus yielding more precision, higher tolerances, and lower labor costs. Completed sections of curtain wall then are transported to the building site for attaching to the building structure. Each mullion member has extruded splines on its interior surface and an exterior shelf. Sills, heads, and intermediate horizontal members have similar structures which include pressure plates. The pressure plates contain holes which correspond with holes drilled on the exterior shelf of the mullion. The method also emphasizes an efficient means of anchoring curtain walls to a slab or structure.
A hollow body hole punching apparatus is disclosed in U.S. Pat. No. 6,561,065 Ranalli, 2003) wherein an “elongated hollow body” or mullion is described as the typical workpiece. An expandable die is inserted into the mullion which rests upon a support table. A positioning bar is connected to the die and manipulates the mullion into alignment with an overhead punch press. The die, which is fabricated with die cavities, is then mechanically expanded, thus preventing collapse of the mullion as the holes are punched.